[Immunohistochemical observation of actin in viral myocarditis]

10 specimens of heart in autopsy were immunohistochemically studied by using anti-actin(At) antibody. In 5 cases with definite or suspected viral myocarditis according to Dallas criteria, actin in myocardium showed focal or diffuse weak staining, and occasionally showed focal absence of staining. In 2 cases with myocardial infarction, actin showed large pieces absent of staining, while actin in 3 cases with non-cardiac death showed strongly positive, well-distributed staining. The results indicated the immunohistochemical observation of actin in myocardium is useful for improving the sensitivity in diagnosing viral myocarditis and differentiating the slight injuries of myocytes caused by ischemia or inflammation.